490 



EXCRETION 



Pig. 1 88. Diagram of Blood- 

 vessels of Kidney (Klein, after 

 Ludwig). ai, interlobular ar- 

 tery; vi, interlobular vein; 

 g, glomerulus, to which an 

 afferent artery is seen coming 

 from the interlobular artery, 

 and from which an efferent 

 artery proceeds to break up 

 into a capillary network sur- 

 rounding the renal tubules; 

 vs, vena stellata; ar, arteriae 

 rectae ; vb, leash of venae rectae ; 

 vp, vascular network round 

 ducts at apex of a papilla. 



Fig. 189. Diagram of Renal Tubule (Klein). 

 A, cortex ; a, layer of cortex immediately under 

 capsule containing no Malpighian corpuscles; 

 a', inner layer of cortex devoid of Malpighian cor- 

 puscles; B, boundary layer; C, papillary zone of 

 medulla; i, Bowman's capsule; 2, neck of cap- 

 sule; 3, proximal convoluted tubule; 4, spiral 

 tubule; 5, descending part of Henle's loop- 

 tubule; 6, the loop; 7, 8, and 9, ascending limb 

 of loop-tubule; 10, irregular tubule; n, distal 

 convoluted tubule; 12, junctional tubule; 13, 

 collecting tubule in a medullary ray or pyra- 

 mid of Ferrein; 14, collecting tubule in the 

 boundary layer; 15, large collecting tubule 

 ending in a duct of Bellini. 



